The body of a university student is found at Songnae Mountain. Yubin uncovers clues at the scene and the case mirrors the murder of Yubin's fiancee.

Yubin's friend Hyunwoo identifies the prime suspect and exposes him on television while Junghwan secures crucial CCTV footage but falls into danger.

Junghwan undergoes surgery but remains unconscious. Joongryeok hunts down the voice phishing gang and finds their hideout.